It's people living in the past. Wonder what their excuse will be when the younger players reach their prime and Canada is no longer as dominant in the international tournaments. The past decade of the World Juniors have shown that Canada's younger players are no longer as good as a couple other countries. USA (and arguably Finland) has passed them IMO, and it'll translate to Olympic success starting in 2026.
The standard "5-10" years we've been hearing for decades. But I actually don't doubt it is possible this time. There isn't some innate Canadian ability to play hockey. Success is a result of population, participation, organization, investment and culture. The elements are there for the US to overtake Canada at the senior level esp. with the amount of investment from the NHL there.
On the one hand, cheering for this is fine -- you follow the players in your country, you relate to them, you might even know some of them. All good. On the other hand (and I'm sure no one here is guilty of this), deriving some personal pride from it or doing vicarious battle with other fans over it is really quite pitiful and small-minded, moreso than the schoolyard "my dad could beat up your dad," because it has even less to do with you.